Two British students are apologizing after their Twin Towers Halloween costumes sparked outrage around the world.

Amber Langford and Annie Collinge, both 19, were given shopping vouchers after winning a Halloween costume contest dressed as the World Trade Center towers at Rosies nightclub in Chester last week, Metro reported.

Labeled North Tower and South Tower, the girls' costumes featured flames, explosions and even planes hanging from windows.

Reaction was harsh when photos of the girls hit social media.

Many Twitter users expressed outrage at the nightclub for letting the girls in and rewarding their offensive handiwork. Others took out their frustration on the girls themselves, who eventually deactivated their Twitter accounts, according to Buzzfeed.

"We never meant to be offensive, but we apologize if any offense was caused," the Chester University students told The Sun. "The idea was to depict a serious, modern-day horror that happened in our lifetime and was not intended as a joke."

The company that operates Rosies said the decision to award a prize to the girls was a "serious error of judgment" made by a DJ.